1. Field of the Invention
The invention relates to an optical touch control device, and more particularly, to a combinable and expandable optical touch control device.
2. Description of the Prior Art
Common types of touch sensing devices include capacitative, resistive, and optical. A capacitative or resistive touch control device determines a touch event via detecting variations in electrical characteristics (capacitance or resistance) generated when the human body touches a touch panel. Such detection methods are not conducive to large-dimension applications, and thus optical touch control systems have been developed for these operations.
Optical touch control technologies dispose an infrared (IR) light source around a touch area, and shadows generated by objects on the touch area that obstruct the infrared light source are detected using IR Cameras and CMOS Sensors. Information such as direction, height and width of the shadows is captured, and in turn used to determine a position of a touch point.
An optical touch control system has the advantage of cost-effectiveness in that, regardless of the dimensions of the touch area, only two sensors need to be placed at corners of the touch area. In particular, the larger the touch area, the lower a unit production cost for the touch screen may be obtained. For optical touch screens of different dimensions, however, resolutions and focal distances of the sensors, as well as lighting ranges of the infra-red light source, need to be fine-tuned, and adjustments have to be made to reflective/light-emitting borders of the touch screens. Therefore, the user is unable to arbitrarily expand dimensions of smaller optical touch screens. Furthermore, touch screens are often rectangular in shape, and do not allow arbitrary combinations into touch screens of other geometrical shapes. Therefore, the prior art leaves much room for improvement.